The Neotropical Fomitiporia (Hymenochaetales, Basidiomycota): the redefinition of F. apiahyna s.s. allows revealing a high hidden species diversity

The Neotropical species Fomitiporia apiahyna was repeatedly shown to form a lineage with multiple sublineages that could correspond to different phylogenetic species, hence forming a highly diverse species complex. Due to their inconspicuous morphological features, species delimitation in this complex needs an integrative taxonomic perspective. In this study, we have performed multilocus molecular (ITS, ncLSU, TEF-1α, and RPB2) analyses in order to delimit the phylogenetic placement of specimens previously determined as F. apiahyna and to determine the phylogenetic diversity in term of clades that could be equated to species. Both morphological, ecological, and distribution data have been integrated to better delimit species boundaries. The F. apiahyna sensu lato lineage was shown to encompass four clades, corresponding to the four species: F. apiahyna sensu stricto, which is confirmed based on specimens originating from the type locality and here epitypified; F. nubicola sp. nov., proposed based on specimens found on Drimys angustifolia and Drimys sp., a relic plant species distributed exclusively in fragmented forests of high altitude areas in southern Brazil; F. conyana sp. nov., proposed from specimens previously suggested as the closest to F. apiahyna s.s.; and F. murrilli sp. nov., proposed based on specimens found on the locally exotic Eucalyptus sp. and another undefined angiosperm in southern Brazil. Additionally, Phellinus elegans emerged from the synonymy of F. apiahyna and the new combination Fomitiporia elegans is proposed. An identification key to the Neotropical species with pileate basidioma also is provided. Phylogenetically delimited species are strongly supported by ecological data, and in the case of F. conyana by clear-cut morphological data. It is expected that, with the redefinition of F. apiahyna s.s., other phylogenetic species will emerge in the near future.